Bump requests dependency to 2.x for Unicode handling
Move test setup to script & update README

This avoids the README drifting out of sync
Use tox for testing multiple versions

* Add a simple test-runner which handles starting and stopping Solr
* Added a basic tox.ini for Python 2.6, 2.7 and 3.3 with and without
  Tomcat to keep us honest about extra_requires…